The invention is generally related to arc lamp bulbs and, more particularly, to an apparatus and method for monitoring the life of arc lamp bulbs.
Arc lamp bulbs are a common light source for many optical systems, such as front and rear projection systems. Arc lamp bulbs exhibit high efficiency, good color balance and good geometric matching to the optical systems.
However, the lifetime of a typical arc lamp bulb is usually between 2,000 and 8,000 operating hours, depending on the manufacturer, output power, filling of the lamp, etc. This lifetime is considerably less than the lifetime of systems and apparatus in which the arc lamp bulb is integrated, e.g., monitors, TVs and projectors. In addition, the above lifetime values are averages and part-to-part variations are quite significant.
Thus, it is difficult to predict when an arc lamp bulb will burn out, making it difficult to know when the arc lamp bulb should be replaced. Furthermore, due to this lack of predictability, burn out of an arc lamp bulb is often unexpected, and a user may not have a replacement bulb on hand when the arc lamp bulb burns out.
Thus, an unaddressed need exists for an apparatus or method that accurately predicts the remaining life of an arc lamp bulb, to enable the user to obtain a spare arc lamp bulb prior to the failure of the current arc lamp bulb.
The invention provides an apparatus and method for monitoring the life of arc lamp bulbs.
Briefly described, in architecture, the apparatus can be implemented as follows. The apparatus for monitoring arc lamp bulbs includes (1) a memory for storing a predetermined threshold property value for an arc lamp bulb; (2) an arc lamp bulb property value sensor for acquiring a current arc lamp bulb property value; and (3) a control circuit for comparing the current arc lamp bulb property value with the predetermined threshold property value, and generating an end-of-life notification signal when the current arc lamp bulb property value meets the predetermined threshold property value.
The invention can also be viewed as providing a method for monitoring the life of arc lamp bulbs. The method can be broadly summarized by the following steps: (1) acquiring a predetermined threshold property value for an arc lamp bulb; (2) acquiring a current arc lamp bulb property value; (3) comparing the current arc lamp bulb property value with the predetermined threshold property value; and (4) generating an end-of-life notification signal when the current arc lamp bulb property value meets the predetermined threshold property value.
The invention provides an end-of-life notification signal, indicating that the arc lamp bulb should be replaced, close to the end of the useful life of the arc lamp bulb, but before the bulb actually burns out. The threshold property value is chosen to correspond to a point in the life of the arc lamp bulb that precedes the actual burn out of the bulb.
In an embodiment, in acquiring a current arc lamp bulb property value, more than one current property of the arc lamp bulb can be acquired, and, in comparing each current arc lamp bulb property value with a respective predetermined threshold property value, an end-of-life signal can be generated if any of the comparisons indicates an acquired property value has reached its predetermined threshold value. Alternatively, when values are acquired for more than one property value, the value of an expression involving these acquired values can itself be compared with a corresponding predetermined threshold value.
Other features and advantages of the invention will become apparent upon examination of the following drawings and detailed description. It is intended that all such additional features and advantages be included herein within the scope of the invention.